Treacher Collins syndrome is a rare birth defect that often causes deformities in the size and shape of various facial features. Affected areas of the face include the ears, eyelids, cheekbones, and the upper and lower jaws. 

Treacher Collins syndrome is also known as Franceschetti-Zwalen-Klein syndrome or mandibulofacial dysostosis. The condition occurs in one in every 50,000 live births, according to the National Institutes of Health.

An English physician named Edward Treacher Collins was the first to describe this syndrome in 1900. Children who are affected may experience a range of symptoms from mild to severe. In some cases, symptoms are so mild that they can only be detected by an expert.

However, in other cases the physical signs of Treacher Collins syndrome can be very obvious. Symptoms may include underdeveloped cheekbones and jawbones, deformity of the roof of the mouth (cleft palate), eyelid problems and ear deformities. Because deformities of the outer and middle ear are common, hearing loss often accompanies the syndrome.